Which property is required for protective ground cables?

• A. Aluminum, stiff, high resistance, unjacketed
• B. Copper, rigid, high resistance, jacketed
• C. Copper, flexible, high resistance, jacketed
• D. Copper, extra flexible, low resistance, jacketed

Answer: (D)

Protective ground cables must be able to carry fault current safely while standing up to field conditions, so their material, flexibility, and insulation are chosen to support that duty. Copper is used because it provides the lowest resistance and excellent conductivity, which helps fault current travel quickly to trip protective devices. Extra flexibility is important to route the conductor through tight spaces and around equipment without damaging insulation or the strands. Low resistance means less voltage drop and less heat during a fault, improving reliability and safety. A jacket protects the conductor from moisture, chemicals, abrasion, and mechanical wear, ensuring the grounding path remains intact over time. Choices that use heavier or stiffer materials, higher resistance, or are unjacketed don’t perform as reliably in the demanding conditions where protective grounds must operate.